Scanning Electron Microscopy versus Transmission Electron Microscopy for Material Characterization: A Comparative Study on High-Strength Steels. (4th May 2021)

• Record Type: Journal Article
• Authors: Brodusch, Nicolas; Brahimi, Salim V.; Barbosa De Melo, Evelin; Song, Jun; Yue, Stephen; Piché, Nicolas; Gauvin, Raynald
• Other Names: Stylianou Andreas Academic Editor.
• Is Part Of: Scanning. Volume 2021(2021)
• Publication Date: 2021-05-04
• Subjects: Scanning electron microscopy -- Periodicals; 502.825
• DOI: 10.1155/2021/5511618
• Languages: English
• ISSNs: 0161-0457

Abstract

Abstract : The microstructures of quenched and tempered steels have been traditionally explored by transmission electron microscopy (TEM) rather than scanning electron microscopy (SEM) since TEM offers the high resolution necessary to image the structural details that control the mechanical properties. However, scanning electron microscopes, apart from providing larger area coverage, are commonly available and cheaper to purchase and operate compared to TEM and have evolved considerably in terms of resolution. This work presents detailed comparison of the microstructure characterization of quenched and tempered high-strength steels with TEM and SEM electron channeling contrast techniques. For both techniques, similar conclusions were made in terms of large-scale distribution of martensite lath and plates and nanoscale observation of nanotwins and dislocation structures. These observations were completed with electron backscatter diffraction to assess the martensite size distribution and the retained austenite area fraction. Precipitation was characterized using secondary imaging in the SEM, and a deep learning method was used for image segmentation. In this way, carbide size, shape, and distribution were quantitatively measured down to a few nanometers and compared well with the TEM-based measurements. These encouraging results are intended to help the material science community develop characterization techniques at lower cost and higher statistical significance.